A stereoscopic 3D display usually presents an observer with images with parallax from individual right and left eye viewpoints. There are two methods of providing the two eyes of the observer with the parallax images in a time sequential manner. In one method, the observer utilizes a pair of shutter or 3D glasses which transmit or block light from the viewer's eyes in synchronization with alternating the left/right image display. Similarly, in another method, right eye and left eye viewpoints are alternatively displayed and presented to the respective eyes of the observer but without the use of 3D glasses. This second method is referred to as autostereoscopic and is sometimes desirable for stereo 3D viewing because separate glasses are not needed though there is limited permissible head motion.
A liquid crystal display (LCD) is a sample and hold display device such that the image at any point or pixel of the display is stable until that pixel is updated at the next image refresh time, typically 1/60 of a second or faster. In such a sample and hold system, displaying different images, specifically displaying alternating left and right images for an autostereoscopic display, requires careful timing sequencing of the light sources so that, for example, the left eye image light source is not on during the display of data for the right eye and vice versa.
When operating a stereoscopic 3D display on an LCD panel, where left and right frames are written to the LCD sequentially, left/right crosstalk can occur as the new image is drawn on the LCD. Since the LCD is a sample and hold display device, lines of the old image will persist until the new data is written, and then after the new data is written there is a time (the LCD response time) before the old image data fades away and the new image data is fully present. Further, the transition or response time of the LCD panel is often dependent on the difference in the brightness or gray level of the two images such that a white to black (W-B) or black to white (B-W) transition can take much less time than a gray-to-gray (G-G) transition time. For any of these cases, if the left or right eye sees the image on the LCD before the left or right image respectively has fully stabilized and the left or right backlight is on, then crosstalk may occur and the stereoscopic 3D effect will be degraded